Process for resolving a cyclic hydroxy acid



tates ate nite acid). It may be recovered by alkalizing the acid mother 3,043,865 liquors from which the enantiomorphs of compound I PROCESS FOR RESOLVING A CYCLIC have been precipitated.

HYDRQXY ACID V By this process, both the deXtro-rotary enantiomorph of Gmrd i andilean Cerede Dugny 5 lj3-hydroxy-3-carboxy-6-methoxy-9afi-methyl-1,2,3a,8,9,-

France, assrgnors, by mesne assignments, to Rousseb. 9a heXahydrOA3(3a) benZ[61indene substantially it e e UCLAF, S.A., Paris, France, a corporation of France N Drawing Filed May 7, 1959, 811531 from its optical antipode, and the levo-rotary enantio- Claims priority, application France June 3, 1958 morph of B- y yyl y Claims. (Cl. 260-401) 1,2,3a,8,9,9a -heXahydro-A benzo[e]indene, substan- 10 tially free from its optical antipode, can be obtained in The present invention relates to the respective dextrogood yields. rotary 'y antipodes of Y Y- The following examples illustrate the invention withboXyl 6 me 0X3 -9afi-methyl 1,2,3a,8,9,9a-hexahydr0 out limiting the same. More particularly, it is possible to A -benzo[e]indene having the structural formula: vary the nature of the solvents or decompose the salts of compound I with an acid other than hydrochloric acid without departing from the scope of the invention. Moreover, the salts of the enantiomorphs of compound I may be formed with D-( --)-threo-1-(p-nitrophenyl)-2-aminopropane-1,-3-diol, but this renders the process somewhat OH: OH

less economical. 000E The temperatures given are in degrees centigrade. The W (I) melting points'are the instantaneous melting points as their intermediate amine addition salts with l-(p-nitrodetermmafd on a Maquenne block phenyl)-2-arnino-propane-1,3-diol, and the process resolv- EXAMPLE the antlpodes- 1 Isolation of the Dextro-Rotary and Lew-Rotary Emmzio- It also relates to its two enantiomorphs as nove mmorphs of 1B Hydmxy 3 Carb0xy 6 Meflwxy 9afl dustnal products Methyl-1,2,3a,8,9,9a-Hexahydra-A Benz0 [e] indene It is of great interest to have available a simple and in- T ON OF THE COMPLEX WITH L expensive process for the resolution of compound I, which compound is useful as an intermediate in the synthesis 5 3 5 1 (P'NI'PROPHENYL) 2 AMINO'PROPANE f l9-norsteroids and other 0 ticall active steroid P y 7.31 gm. 0.0345 mol.) of L-(+)-threo-1-(p-n1trohormones. The process for producing 19-norsteroids d phenyl)-2-am1nopropane-1,3-d1ol and 60cc. of methanol from the racermc acid compound I 1s escrlbed by C mm are added to 9 g of racem c 118 hYdroXY 3- et al., Abstract of Papers-134th Meeting of the Amercarboxy-6-methoxy-9ap-methy1-1,2,3a, 8,9,9a-hexahydrolcan Chemical Society, 1958, 14 0 It 1s readi y aPPar As(3a) benzo[elindeneg P p rd g to D. K.

ent that by resolving the racemic acid compound I it is possible to work with the desired enantiomorph at an l f Chem 3769 the conearly stage of the synthesis. The racemate of compound tamer 15 Closed the conmnts agltated for about I has been described by D. K. Banerjee et al., J. Am. 40 one-half. hour mm F i sqhmon has taken place Chem. Soc 78, 3769 (1956), under the name: of The amino-propanediol is in ashghtly molar excess with hydrOXy 8 B methy1 4,5 (4r h y ben 3(9) hydri respect to the racemic benzo[e]1ndene. The resulting yeldene 3 carboxylic acid. low solution is allowed to stand at room temperature for one-half hour and then 210 cc. of isopropyl ether are e have found at the race 0 acid 60 pound I can slowly added accompanied by agitation After all the th i be resolved by the following proce ure W 1ch consists es 0 either has been added crystal]. ation is I hated by f 'thanot' ll ti o i sentlauy of Ormmg salt W p 10a y ac ve rgan c scratching and the mixture s allowed to stand for one base namely L-( -threo-1 (p-nitrophenyl -2-aminohour 1n the dark. The crystals of the salt formed by the Propane (1101 m the presence of a polar Orgamc 501 dextro-rotary base with the levo-rotary acid are filtered vent, and adding a second organic solvent adapted to make one of the salts of the two enantiomorphs of compound I Off l room temperature and are alien mturated successwe' ly with 20 cc. and 15 cc. of a mixture of methanol and become relatively insoluble, so that it becomes possible to separate and then liberate the two enantiomorphs by isopropyl ether in a ratio of 1.3.5. The wet crystals are acidification. Lower alkanols, such as methanol or 'then dried m avacuum 53 of ff ethanol, are preferably used as polar organic solvents, the f g f fi "i g f 120-122 1 Q" second organic solvent being, preferably, isopropyl ether. 55 [MD m met ano For ana'ysls This process makes it possible to separate the two the product 18 recrystalhzed from Water whereby enantiomorphs rapidly and with good yields, giving the precinct 'Y q Y one'half molecule of Water Is desired enantiomorph substantially free of its optical antiobtamed 111.1611 13 m h fo.rm of Pale yellow prisms or poda In addition it is Very e con 0 mi 6 al The platelets which are soluble in water, methyl or ethyl althre0 1 (p nitro ph amin 01301) a ne 1,3 dio1 which cohol and acetone, poorly soluble in benzene or chlorois used as the resolving agent is a valueless lay-product of form msolubde m 180p r 0p Y1 fi decompos: m dflut? the synthesis of chloramphenicol and is obtained by the 3 3; gi i si g {f' ktijg fi gh ygg z 35 2 a. process described by Velluz et 21]., Bull. Soc. Ch1m., 1953, AnaIySI-S C2SH3GOBN2, H2O moL Wt 495.52.

page 342.

It has the structural formula giiiai'b rfi i, 3%,- N, 5.65%. Found. C 11TH, Loss of weight at C.-=1.8% (calculated 1.82%). This compound is not described in the literature and I is the hemihydrate of the acid addition salt of levo-rotary 7Q 1,B-hydroxy-3-carboXy-6methoXy-9afl-methyl 1,2,3a,8,9,- and the following physical characteristics: M.P.=162 9a-heXahydro-A -benzo[e]indene and L-(+)-threo-1- 163 C., M1 +2 8:2.(c.=1% in .05 N hydrochloric (p-nitrophenyl)-2-amino-propane-l,3-diol.

spaasczs (B) ISOLATION OF LEVO-ROTARY 1fl-HYDROXY-3-CAR- BOXY-6-METHOXY 9a}? METHYL 1,2,3a,8,9,9a -HEXA- HYDROA BENZO [E] INDENE 7 gm. of the saltobtained in A above are dissolved at 4050 C. in 250 cc. of water, and 22.5 cc. of 1 N hydrochloric acid are. then added to the solution while stirring. The levo-rotary acid begins to precipitate. The solution is allowed to stand for one hour at room temperature and is then filtered. The precipitate is filtered ofi and triturated twice in 25 cc. of water. The preciptate is then dried in a vacuum over P 3.71 gm. of the raw levorotary acid are obtained which are then recrystallized from 60 cc. methanol containing water. The yield is 86% based on the amount of racemic acid. The novel compound, levo-rotary 1B-hydroXy-3-carboxy-6-methoxy- 9aB-methyl-1,2,3a,8,9,9a-hexahydro A -benzo[e]indene substantially free from its optical antipode, which is not described in the literature, is obtained in the form of white needles and is soluble in dilute alkaline solutions, alcohol, ethyl ether and acetone, poorly soluble in benzene and chloroform, and very slightly soluble in water, dilute acidic solutions and isopropyl ether. M.P.=223- 225 C., [a] =l20 (c.'=1% in methanol).

Annlysis.-C H O mol. wt. 274.30. Calculated: C, 70.05%; H, 6.61%. Found: C, 70.0%; H, 6.6%.

By rendering the mother liquor from the acidification step alkaline, the resolving reagent can be recovered, The yield from this recovery procedure is about 90% of the starting L-( -threo-1-(p-nitrophenyl) -2-amino-propane- 1,3-diol.

(C) ISOLATION OF DEXTRO-ROTARYlfl-HYDROXY-3- CAREOXY-6-METHOXY-9afi-METHYL-l,2,3tt,8,9,9a-HEXA- HYDROA BENZO [E] INDENE The solvents in the mother liquor from the filtration step in the preparation of the salt of the levo-rotary enantiomorph described under A above are distilled off in vacuo on the water bath. The yellow gummy residue, the acid addition salt of dextro-rotary LB-hydroxy-3- carboxy-16-methoxy9a;8 methyl 1,2,3a,8,9,9a-hexahydro- M -benzo[e]indene and L-(+) threo 1 (p-nitrophenyl)-2-amino-propane-1,3-diol, is then dissolved in 60 cc. water and 20 cc. 1 N hydrochloric acid are added dropwise to the solution while stirring. The dextro-rotary 1,B-hydroxy-3-carboxy-6-methoxy-9afi-methyl 1,2,3a,8,9,- 9a-hexahydro-A -benzo [e]indene precipitates out in finely divided form. The mixture is allowed to stand for a few minutes, the prcciptate is filtered ofi, triturated three times with cc. water and dried in vacuo. 4.61 gm. of the raw product having a MP. of 214 C. are obtained. By recrystallization from 80% methanol, 3.98 gm. (representing a yield of 88.5% of the dextro-rotary 1/3- hydroxy-3-carboxy-6-metho1W-9aflmethyl 1,2,3a,8,9,9ahexahydro-A -benzo[eJindene substantially free from its optical antipode are obtained, having a M.P. of 223-- 225 C., [a] =+-118 (c.=1% in methanol). The dextro-rotary compound, like its levo-rotary enantiomo ph, is obtained in the-form of white needles and has the same solubility properties. The resolving reagent is recovered in the manner described under B above.

While We have illustrated various specific embodiments of our invention, it will be readily apparent to one skilled in the art that the invention herein described is not limited to these embodiments and that various changes and modifications may be made without departing from the spirit of the invention or the scope of the appended claims.

We claim:

1. The process of resolving racemic 1/3-hydroxy-3 carboxy 6 methoxy 9afi methyl 1,2,3a,8,9,9a hexahydro-A -benzo[elindene into its levo-rotary and dextro-rotary enantiomorphs which comprises dissolving said racemic benzo[e]indene in a solution of L-(+)-threo-1- (p-nitrophenyl)-2-amino-propane-1,3-diol in a slightly molar excess with respect to said benzo-[e]indene in a lower alkanol at about room temperature to form an acid addition salt of said benzo[e]indene and said aminopropanediol, adding to said solution a second organic solvent selected from the group consisting of chloroform and isopropyl ether, crystallizing the acid addition salt of the levo-rotary enantiomorph at about room temperature and separating the precipitated crystals from the mother liquor. 1

2. The process of claim 1, wherein said lower alkanol is methanol.

3. The process of claim 1, wherein said second organic solvent is isopropyl ether.

4. The process of resolving racemic lp-hydroXy-3- carboxy 6 methoxy 9afi methyl l,2,3a,8,9,9a hexahydro-A -benzo [e]indene into its levo-rotary and dexro-rotary enantiomorphs which comprises dissolving said racemic benzo[e]indene in a solution of L-(+)-threo-l- (p-nitrophenyl)-2-amino-prop-ane-1,3-diol in a slightly molar excess with respect to said benzo[e]indene in a lower alkanol at about room temperature to form an acid addition salt of said benzo[e]indene and said aminopropanediol, adding to said solution a second organic solvent selected from the group consisting of chloroform and isopropyl ether, crystallizing the acid addition salt of the levo-rotary enantiomorph at about room temperature, separating the precipitate crystals from the mother liquor, dissolving said crystals in water, acidifying to precipitate the levo-rotary enantiomorph and separating said levo-rotary enantiomorph.

5. The process of resolving racernic lfi-hydroXy-3- carboxy 6 rnethoxy 9afi methyl 1,2,3a,8,9,9a hexahydro-A -benzo[e]indene into its levo-rotary and dextro-rotary enantiomorphs which comprises dissolving said racernic benzo[e]indene in a solution of L-(+)-threo-l- (p-nitrophenyl)-2-amino-propane-1,3-diol' in a slightly molar excess with respect to said benzo[e]indene in a lower alkanol at about room temperature to form an acid addition salt of said benzo[e]indene and said aminopropanediol, adding to said solution a second organic solvent selected from the group consisting of chloroform and isopropyl ether, crystallizing the acid addition salt of thelevo-rotary enantiornorph at about room temperature, separating the precipitated crystals from the mother liquor, evaporating said mother liquor, separating the precipitated acid addition salt of the dextro-rotary enantiomorph, dissolving said acid addition salt in water, acidifying to precipitate the deXtro-rotary enantiomorph and separating said dextro-rotary enantiomorph.

References Cited in the file of this patent UNITED STATES PATENTS 2,921,959 Amiard Ian. 16, 1960 2,991,307 Amiard et al. July 4, 1961 FOREIGN PATENTS 785,014 Great Britain Oct. 23, 1957 OTHER REFERENCES Banerjee et al.: Jour. Am. Chem. Soc, vol. 78, pp. 3769- (1956). (Copy in Pat. Olf. Scientific Library.) 

1. THE PROCESS OF RESOLVING AGENT 1B-HYDROXY-3CARBOXY-6-METHOXY-9AB-METHYL-1,2,3A,8,9,9A- HEXAHYDRO-$3(3A) - BENZO(E)INDENE INTO ITS LEVO-ROTARY AND DEXTRO-ROTARY ENANTIOMORPHS WHICH COMPRISES DISSOLVING SAID RACEMIC BENZO (E) INDENE IN A SOLUTION OF L-(+)-THREO-1(P-NIROPHENYL)-2-AMINO-PROPANE-1,3-DIOL IN A MOLAR EXCESS WITH RESPECT TO SAID BENZO-(E) INDENE IN A LOWER ALKANOL AT ABOUT ROOM TEMPERATURE TO FORM AN ACID ADDITION SALT OF SAID BENZO (E) INDENE AND SAID AMINOPROPANEDIOL, ADDING TO SAID SOLUTION A SECOND ORGANIC SOLVENT SELECTED FROM THE GROUP OF CHOROFORM AND ISOPROPYL ETHER, CRYSTALLIZING THE ACID ADDITION SALT OF THE LEVO-ROTARY ENANTIOMORPH AT ABOUT ROOM TEMPERATURE AND SEPARATING THE PRECIPITATED CRYSTALS FROM THE MOTHER LIQUOR. 